wasting my time with comp cams!!

clark98gt · Mar 3, 2012

I bought a set of comp 270s from a guy on here figuring I would put them in as I do the PI swap. Well after spending 2 days degreeing them in at 114 instead of the cam cards 109, thinking better safe than sorry, it turns out for some reason I have no ptv clearance in the 7 and 8 cylinders but I do in the 5 and 6. I didnt even bother trying the other cylinders. I discovered this when I was just putting the rollers in. If I use the PI cams I have, will the after market valve springs I had installed still be fine?

vermilion · Mar 3, 2012

yes theyll be fine.

clark98gt · Mar 3, 2012

Ok thanks. I was hoping I wouldn't have to pull the heads, again.

MadStang · Mar 3, 2012

clark98gt said:
Ok thanks. I was hoping I wouldn't have to pull the heads, again.

You should always degree per the cam card specifications. I'd recommend giving it a retry, it doesn't take that long to degree cams.

clark98gt · Mar 3, 2012

Wouldn't me degreeing them at 109 actually make the ptv tighter?

rz5.0 · Mar 3, 2012

114 so is that considered 5Â° advanced in cam timing? Advance timing brings the intake valve to the piston right?

MadStang · Mar 3, 2012

rz5.0 said:
114 so is that considered 5Â° advanced in cam timing? Advance timing brings the intake valve to the piston right?

114 is actually retarded. If He advanced the camshaft 5 degrees it would bring the Intake/Exhaust valve closer to the piston ATDC. It would in turn reduce the PTV but that being said, it's always a good idea to verify by following cam card specs before you deviate.

rz5.0 · Mar 3, 2012

Ha I see.. Next engine im buying a degree wheel.. I wanna learn to use one of those things.. Thanks MadStang

clark98gt · Mar 4, 2012

I understand what you are saying but 1 when I put the passenger side cam in I couldnt even turn it over without filing the cam keyway. and 2 no it doesnt take that long to put everything back together to re-degree the cams but it seems kinda senseless to advance the cams when they make contact being retarded 5 degrees off of the recommended specs. Plus when I researched these cams the 109 number is what is recommended for 99-04 2vs, I'm assuming they must have more ptv clearance than my PI swapped 2v. I came up with the 114 number because that was apparently what comp had decided to change to when people where having ptv issues.

MadStang · Mar 4, 2012

There is no difference in PTV from npi to PI. the valve hits on the flat outer edge not in the dish of the piston.

are the cams new? I know on my used cams there was a nick in the cam and it caused it to seise all movement. deburred it and spun nice and easy.

Willis_98GT · Mar 4, 2012

MadStang said:
There is no difference in PTV from npi to PI. the valve hits on the flat outer edge not in the dish of the piston.

are the cams new? I know on my used cams there was a nick in the cam and it caused it to seise all movement. deburred it and spun nice and easy.

on my first motor with 270s/pi heads a valve hit the inside and the outside of the piston. it was pretty crazy.

cams arnt exactly a waste, a lot of ppl dont run them because it seems like its quite a bit of work to get them degreed and the cost of springs etc. and thats before i even include shop labor.

from personal experience i fucking love my 270s. did you do the pi mainfold? if so do you remember the 4grand-redline power increase from getting rid of the npi intake?

the 270s with pi heads on your car depending on if you go full exhaust or not will be like that same comparison like times 4 lol granted i lost a little bit of low/mid power but that was a decision that i made when i bought the cams because i love the top end now. you would be supprised what cams. most people are cam haters, i however am not! good luck with your decision!! let us know if you have any more questions

clark98gt · Mar 4, 2012

I don't think upgrading the cams is a waste, just buying these ones was apparently. The cams spin just fine until I install the 7 or 8 cylinder rollers then when turning the engine over by hand, as soon as the valve tries to open there is contact.

Venomized · Mar 4, 2012

Are you sure its the cams and not the springs? You may have some weak springs.

vermilion · Mar 4, 2012

what timing method are you using?

clark98gt · Mar 4, 2012

I am using the comp springs that were recomended to use with those cams and I degree the cams using Modular Head Shops way. 0.50 before max lift and 0.50 after max lift. I'm going to mess with it a little more tomorrow after work before writing them off for sure.

97stanger · Mar 4, 2012

what are the specs on the comp 270s?

clark98gt · Mar 4, 2012

Specifications		Intake	Exhaust
RPM Range:	Valve Lash:
Valve Timing:	Duration:
Lobe Separation:	Duration @ .050" Lift:
Intake Centerline:	Valve Lift:
	Lobe Lift:
Valve Timing @ 0.05 Lift: